where \(M\)  is the mass of the black hole,
\(R\)  is the inner radius of
the disc, \(\dot{M}\)  is the accretion rate and \(r\)  is the radius of
disc. The disc is assumed to be radiating as a black body, hence the energy flux per unit area is given by [1]}
\(F(r) \simeq \frac{\sigma T^{4}}{4\tau } = Q_{vis}^{+}\) 
